Re: [RFC] iio: light: acpi-als: Enable the light sensor on the Zenbook UX430UQ

From: Kiernan Hager
Date: Mon Nov 20 2017 - 11:52:00 EST


On Sun, Nov 19, 2017 at 11:11 AM, Marek Vasut <marex@xxxxxxx> wrote:
> On 11/19/2017 06:38 PM, Gabriele Mazzotta wrote:
>> 2017-11-19 18:03 GMT+01:00 Jonathan Cameron <jic23@xxxxxxxxxx>:
>>> On Wed, 15 Nov 2017 20:27:54 -0700
>>> Kiernan Hager <kah.listaddress@xxxxxxxxx> wrote:
>>>
>>>> This makes acpi-als properly enable the light sensor on the Zenbook UX430UQ. I don't know if the checking that I do to make sure that the ACPI method exists is sufficient or if it should disable the sensor when the module is unloaded, so input is appreciated on those matters.
>>>
>>> Please wrap descriptions to around 72 characters (leaves room for indentation
>>> in the email thread :)
>>>
>>> This seems very much like a board specific hack. I've cc'd people
>>> who have worked on the driver recently and the acpi list.
>>
>> This is indeed board specific. I know many other laptops of the
>> Zenbook line need something similar and if you look at
>> drivers/platform/x86/asus-wmi.c or any other asus-* driver you'll
>> find several quirks to enable various features.
>
> Maybe that's where it should go . EC0 in the ACPI path seems like
> Embedded Controller to me .
>
>> Kiernan, check commit aca234f6378864d85514be558746c0ea6eabfa8e
>> ("asus-wmi: provide access to ALS control") in particular.
>>
>>>>
>>>> Signed-off-by: Kiernan Hager <kah.listaddress@xxxxxxxxx>
>>>> ---
>>>> drivers/iio/light/acpi-als.c | 16 ++++++++++++++++
>>>> 1 file changed, 16 insertions(+)
>>>>
>>>> diff --git a/drivers/iio/light/acpi-als.c b/drivers/iio/light/acpi-als.c
>>>> index c35e2f8df339..8fd66166f19f 100644
>>>> --- a/drivers/iio/light/acpi-als.c
>>>> +++ b/drivers/iio/light/acpi-als.c
>>>> @@ -179,6 +179,10 @@ static int acpi_als_add(struct acpi_device *device)
>>>> struct acpi_als *als;
>>>> struct iio_dev *indio_dev;
>>>> struct iio_buffer *buffer;
>>>> + unsigned long long temp_val;
>>>> + acpi_status status;
>>>> + struct acpi_object_list arg_list;
>>>> + union acpi_object arg;
>>>>
>>>> indio_dev = devm_iio_device_alloc(&device->dev, sizeof(*als));
>>>> if (!indio_dev)
>>>> @@ -203,6 +207,18 @@ static int acpi_als_add(struct acpi_device *device)
>>>>
>>>> iio_device_attach_buffer(indio_dev, buffer);
>>>>
>>>> + arg_list.count = 1;
>>>> + arg_list.pointer = &arg;
>>>> + arg.type = ACPI_TYPE_INTEGER;
>>>> + arg.integer.value = 1;
>>>> +
>>>> + if (acpi_has_method(als->device->handle, "\\_SB.PCI0.LPCB.EC0.ALSC")) {
>>> So this is poking something on
>>> PCI bus 0
>>> LPC bus B
>>> Somethingbus 0
>>> Ambient light controller.
>>>
>>> I assume there is a better way of establishing this needs to be set?
>>>
>>>> + status = acpi_evaluate_integer(als->device->handle,
>>>> + "\\_SB.PCI0.LPCB.EC0.ALSC",
>>>> + &arg_list,
>>>> + &temp_val);
>>>> + }
>>>> +
>>>> return devm_iio_device_register(&device->dev, indio_dev);
>>>> }
>>>>
>>>
>
>
> --
> Best regards,
> Marek Vasut

That sounds like a good idea. I'll have a look at that file and
possibly apply my patch to that instead.

Kiernan